Nuclear reactors in general and pressurised water nuclear reactors in particular include components such as the reactor containment vessel, steam generators and the pressuriser which are made of low alloy high strength constructional steel lined with a layer of stainless steel and connected by one or more connecting tubes to one or more austenitic stainless steel pipes constituting parts of the primary circuit of the reactor, for example.
The containment vessel of a nuclear reactor is generally cylindrical and has a guide tube for supporting connecting tubes in which is formed a set of connecting tubes for connecting the containment vessel to the pipes of the various loops of the primary circuit.
Steam generators of pressurised water nuclear reactors include a water box having a hemispherical wall constituting the lower part of the steam generator with two connecting tubes welded to two pipes of the primary circuit of the reactor.
The pressuriser of a pressurised water nuclear reactor includes a generally cylindrical jacket having two domed ends, the bottom end having a connecting tube for connection to the primary circuit of the nuclear reactor via an austenitic stainless steel expansion pipe, the top end being connected in the same manner to other austenitic stainless steel pipes.
In all cases the connecting tubes of the component, which are made of constructional steel lined with stainless steel, must be butt-welded to an austenitic stainless steel pipe.